Reasoning with evidence while modeling: Successes at the middle school level

Research in undergraduate physics and in K–12 science education has demonstrated challenges and successes in facilitating student engagement with reasoning practices associated with professional physicists. Here we focus on one important dimension of physics reasoning, using evidence to revise models. While this topic has been explored at the undergraduate level, less is known about younger students’ physics reasoning, especially within the context of modeling and model revision, where measurement tools are less emphasized and where evidence is often observational qualitative data. Here we examine 7th graders’ conversations about pieces of observational scientific evidence in their conceptual models of magnetism. We present a series of cases from a whole class discussion to illustrate students’ productive reasoning using evidence while revising, challenging, and testing their scientific models. These cases illustrate how students reason about evidence in the context of canonical and noncanonical models of magnetism, specifically when different pieces of evidence contradict each other and when running the model is inconclusive. The results capture a variety of complex ways evidence can be productively used in reasoning with models, and, more importantly, show that middle school students’ reasoning shares important similarities with more advanced physics reasoning, which can be leveraged when designing and building future instruction.

Figure 1

One group’s final model that shows something happening inside the magnet and paperclip with noticeable ambiguity. The system is shown at three points in time, when the paperclip is touching the magnet (left), inside the magnetic field but not touching (middle), and far apart (right). In all instances there are small entities inside the magnet and paperclip represented by arrows that are pointed towards each other and dots with various distributions. The magnetic field is drawn around the magnet in the shape of a four-petaled flower. Figure 1c from “Modeling Magnetism With the Floating Paper Clip,” by S. Braden, L. Barth-Cohen, S. Gailey, and T. Young, 2021, Science Scope, 44(6), p. 86. Copyright 2021 by the National Science Teaching Association. Reprinted with permission of the author.

Figure 2

This model shows three positions of the magnet and paperclip, touching (top, point A), nearby within the magnetic field, but not touching (middle, point B), and outside of the magnetic field (bottom, point C). In each image the magnetic field is drawn with concentric circles surrounding the magnet (e.g., point D) and the small entities inside the magnet are referred to as “molecules” as represented by small circles, some of which have arrows (point E). The north pole is represented by “up” arrows and the south pole by “down” arrows. In the instance when the paperclip is touching, all molecules are magnetic. When the paperclip is nearby but not touching, some of the molecules are magnetic, and when far away the molecules are not magnetic.

Figure 3

This model shows three positions, with the paperclip touching the magnet (left), nearby and within the magnetic field (middle), and far away (right). In all instances the magnetic field of the whole magnet is a result of the magnetic fields of the smaller things inside the magnets, in both instances, represented by two bars, a red one and a blue one at the macro and micro levels. The lines indicating the magnetic field are shown getting lighter and lighter in density as you move away from the magnet, demonstrating a decrease in the magnetic field with distance from the magnet.

Figure 4

The experiment performed by Dr. Streatfield.